From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.2 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 973CBC47089 for ; Thu, 27 May 2021 13:46:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7109761358 for ; Thu, 27 May 2021 13:46:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236594AbhE0NsT (ORCPT ); Thu, 27 May 2021 09:48:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39074 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236449AbhE0NsR (ORCPT ); Thu, 27 May 2021 09:48:17 -0400 Received: from mail-ot1-x330.google.com (mail-ot1-x330.google.com [IPv6:2607:f8b0:4864:20::330]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id ED2A1C061760 for ; Thu, 27 May 2021 06:46:43 -0700 (PDT) Received: by mail-ot1-x330.google.com with SMTP id i12-20020a05683033ecb02903346fa0f74dso228756otu.10 for ; Thu, 27 May 2021 06:46:43 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20150623.gappssmtp.com; s=20150623; h=subject:to:references:from:message-id:date:user-agent:mime-version :in-reply-to:content-language:content-transfer-encoding; bh=/XKLXUdZgb1RxrjyfkAzYf1QNJ7nzXzU4iF7iH+4PNw=; b=iTj6Wwz4CGf+MDRw1wd8DSDTpYPytbaRtbdap32xpWB50FP+X0wmHA3GTpwaqruL0K I2+aDZxQ3fKfFl3r8861J5RSolK7InK0h3ZnoFfwZ2ejX4I66gNkW1Dv/l8PoPjIs9Ys nsjzLQdqovv28/IyTDYlZBpFJHHYNnMBojiaTYb503zXCHGPN+2n2TFyOO223ixJSx3o Q+m6c4rKlaYcH3I1vyhDOmTkMpSnw1C8jINniQZPFnQuVOUYNZl5EKdWGGBTQp02XNYe jzj4B72Gbka8vvcaBu/sJXdaelJh/cjm6dSEbcnsL6UQYjGvJNYfOoZfIZ8xuMKuEFO1 eSFg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=/XKLXUdZgb1RxrjyfkAzYf1QNJ7nzXzU4iF7iH+4PNw=; b=WEzuYF+8Y5Bj+wO4aSm/gvLoWPslMYt8iDfMgfWE4q66OuQfOLL4Cx+SNyFWFmwpMl R8eLuHGwqtj5pi+xcjNdOaLQP8IszPkIDYk/eyt1CLZNC18utDmG5Dw3BbnOqapM3014 XE6hoqONSA1gN81oeFUgpMH7/TXufmz78F/ube88bUuM39GMSlIN+f9loQ4OZoznyThv RIyEnQsowunlt/Y2cvx7Eq37/2HJJYmv1NVAYzvcF6Vw/B2fRbnd4SJkw3MU76U1oLyp HR85muhMR0tKABmB6SUtIGUI+8k58/X6O75zcT3IcypdWUFboS4p8QXBBrgf7uFRVXQF Aouw== X-Gm-Message-State: AOAM5314xUqlv9p77PUyYlAzVPtly8eXDjXMLTt91OS82o2lmJ03b0Zd as2iozbJl2jccKmQUx4hJSucGFioxJRhXA== X-Google-Smtp-Source: ABdhPJyuWwjuzcrzHQxBxvpsmU4sMzLkkCHgtooxoD0sv7tq7ERllNF06ycsrJ+To0Kys29HW1rcWQ== X-Received: by 2002:a9d:624a:: with SMTP id i10mr2807749otk.7.1622123203011; Thu, 27 May 2021 06:46:43 -0700 (PDT) Received: from [192.168.1.30] ([207.135.233.147]) by smtp.gmail.com with ESMTPSA id o13sm487170ote.32.2021.05.27.06.46.42 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 27 May 2021 06:46:42 -0700 (PDT) Subject: Re: [PATCH] io_uring: handle signals before letting io-worker exit To: Olivier Langlois , Pavel Begunkov , io-uring@vger.kernel.org, linux-kernel@vger.kernel.org References: <60ae94d1.1c69fb81.94f7a.2a35SMTPIN_ADDED_MISSING@mx.google.com> From: Jens Axboe Message-ID: <3d1bd9e2-b711-0aac-628e-89b95ff8dbc3@kernel.dk> Date: Thu, 27 May 2021 07:46:44 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <60ae94d1.1c69fb81.94f7a.2a35SMTPIN_ADDED_MISSING@mx.google.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 5/26/21 12:21 PM, Olivier Langlois wrote: > This is required for proper core dump generation. > > Because signals are normally serviced before resuming userspace and an > io_worker thread will never resume userspace, it needs to explicitly > call the signal servicing functions. > > Also, notice that it is possible to exit from the io_wqe_worker() > function main loop while having a pending signal such as when > the IO_WQ_BIT_EXIT bit is set. > > It is crucial to service any pending signal before calling do_exit() > Proper coredump generation is relying on PF_SIGNALED to be set. > > More specifically, exit_mm() is using this flag to wait for the > core dump completion before releasing its memory descriptor. > > Signed-off-by: Olivier Langlois > --- > fs/io-wq.c | 22 ++++++++++++++++++++-- > 1 file changed, 20 insertions(+), 2 deletions(-) > > diff --git a/fs/io-wq.c b/fs/io-wq.c > index 5361a9b4b47b..b76c61e9aff2 100644 > --- a/fs/io-wq.c > +++ b/fs/io-wq.c > @@ -9,8 +9,6 @@ > #include > #include > #include > -#include > -#include > #include > #include > #include > @@ -193,6 +191,26 @@ static void io_worker_exit(struct io_worker *worker) > > kfree_rcu(worker, rcu); > io_worker_ref_put(wqe->wq); > + /* > + * Because signals are normally serviced before resuming userspace and an > + * io_worker thread will never resume userspace, it needs to explicitly > + * call the signal servicing functions. > + * > + * Also notice that it is possible to exit from the io_wqe_worker() > + * function main loop while having a pending signal such as when > + * the IO_WQ_BIT_EXIT bit is set. > + * > + * It is crucial to service any pending signal before calling do_exit() > + * Proper coredump generation is relying on PF_SIGNALED to be set. > + * > + * More specifically, exit_mm() is using this flag to wait for the > + * core dump completion before releasing its memory descriptor. > + */ > + if (signal_pending(current)) { > + struct ksignal ksig; > + > + get_signal(&ksig); > + } > do_exit(0); > } Do we need the same thing in fs/io_uring.c:io_sq_thread()? -- Jens Axboe